Proplayer not showing my self hosted videos – mov files

I am struggling with Proplayer. For some strange reason I can no longer watch the videos I have self hosted.

Most of them are mov files.

When I load the pages, posts with the videos on them, the player screen is just black. The preview image I have loaded in comes up but not the video.
No error message – just no video. The spinning load icon just keeps spinning, and spinning and spinning.

If I load a youtube video in, it works perfectly.

I had this working for months and have no idea why it’s causing me issues now.